This invention relates to semiconductor devices, and more particularly to surface-mount packages for integrated circuit devices.
Integrated circuit devices have been housed in dual-in-line plastic packages, referred to as DIP packages, in the bulk of semiconductor manufacture, for many years. These DIP packages have leads which extend through holes in a printed circuit board, and the package itself is mounted flat on the board. More recently surface-mount packaging has been introduced, and this technique eliminates the necessity of soldering leads in holes in PC boards, so the leads and PC board conductors can be closer together and higher densities are achieved. Similarly, edge-mounted packages or modules have been used in an effort to further increase the density of devices, improve cooling and reduce cost. As the density of devices and circuitry on the chips continues to increase, the packaging density must also increase, both at the package level and at the board level, while at the same time providing adequate cooling, and allowing the assembly and soldering of packages and boards to be fast, accurate and non-destructive. In particular, the packaging technique must provide protection for the leads during test, burn-in, and transport, as well as ease of positioning and mechanical support during mounting and soldering and during the life of the system.
It is a principal object of this invention to provide an improved packaging method for semiconductor integrated circuit devices. Another object is to provide an edge-mounted package for semiconductor devices that does not require soldering of leads into through-holes in a printed circuit board. A further object is to provide a surface-mount package for integrated circuits that is mechanically secure during mounting, soldering and operation, yet does not occupy space on the PC board unnecessarily. Still another object is to provide an edge-mount, surface-mount method for integrated circuit devices that allows the leads to be protected during the time from assembly to final system use, and allows accurate positioning of the leads on a PC board.